Based on field data and MB technical bulletins (LI80.57-P-072139, LI92.10-P-065432):
The IBS monitors the battery’s state of health (SoH). If your Mercedes battery is 4+ years old and has degraded internal resistance, the IBS sends "out-of-range" data. The ECU then throws P1D687A as a "sensor malfunction" when, in reality, the battery is just failing. mercedes-benz p1d687a
In the world of modern automotive diagnostics, few things are as anxiety-inducing for a Mercedes-Benz owner as seeing a Check Engine Light illuminated. While generic OBD-II codes (like P0300 for misfires) are well-documented, Mercedes-specific proprietary codes can be far more cryptic. One such code that has been appearing more frequently in service manuals and diagnostic reports is . Based on field data and MB technical bulletins (LI80